Abstract: [Objective] In situ stress field characterization is crucial for underground engineering safety, rock stability evaluation, and resource development. Current research in Guangdong Province is mainly concentrated on deep crustal levels, where stress interpretations predominantly rely on focal mechanism inversion and numerical modelling. In contrast, shallow stress conditions (<500 m) remain insufficiently constrained due to a lack of direct measurements and fine-scale analysis. To address this gap, this study constructs a shallow stress profile for two boreholes (ZK1 and ZK2, both < 500 m deep) in central-southern Guangdong using hydraulic fracturing and ultrasonic imaging data, aiming to refine shallow stress magnitudes, orientations, and occurrence mechanism. [Methods] Borehole imaging was applied to record hydraulic fracture morphology before and after pressurization, ensuring accurate extraction of the principal stress orientation. Pressure curves and overburden stress were combined to determine stress magnitudes. Stress regimes were further characterized using the A_φ parameter, and only intervals demonstrating reliable fracture propagation and stable pressurization response were selected to ensure high-quality stress results. Based on this, a shallow stress profile was established, and the Coulomb failure criterion was used to compute slip tendency (T_s) to evaluate natural fracture stability. [Results] Within 253.8–349.8 m in ZK1, S_hmin ranges from 7.8 to 12.1 MPa and S_Hmax from 13.7 to 21.7 MPa, corresponding to A_φ ≈ 2–3, indicative of a thrust-faulting stress state. In ZK2 at depths of 129.2–471.2 m, S_hmin is 5.8–9.9 MPa and S_Hmax is 9.7–18.2 MPa. A_φ shows a depth-dependent transition: thrust-faulting characteristics (A_φ ≈ 2–3) above 215.3 m, strike-slip stress (A_φ ≈ 1–2) at intermediate depths, and a gradual evolution toward normal-faulting stress (A_φ ≈ 0–1) at greater depths. Hydraulic fractures in both boreholes are predominantly sub-vertical with stable maximum horizontal stress orientations of N18°W in ZK1 and N15°W in ZK2, maintaining standard deviations <10°. Nonetheless, shallow intervals show pronounced azimuth deflection, with ZK1 above ~293 m deviating 23° and ZK2 above ~203 m deviating 29° toward the NNE. This may suggest that fracture-induced heterogeneity weakens the rock mass, modifies local stress anisotropy, and causes the reorientation of S_Hmax. Slip tendency calculations show T_s <0.4 throughout ZK2, indicating good fracture stability, whereas in ZK1, clusters within 290 ± 30 m reach T_s ≈0.6 near the frictional instability limit, accompanied by elevated S_Hmax relative to predicted trends. This implies higher reactivation potential and mechanical risk. [Conclusions] ZK1 is dominated by thrust-faulting stress with S_Hmax trending ~N18°W. ZK2 exhibits a progressive transformation from thrust to strike-slip to normal-faulting stress state as depth increases, with S_Hmax consistently oriented between N15°W and N18°W. The shallow stress field (<500 m) is different from that of the deeper crust (>5 km), where strike-slip and normal-fault regimes dominate due to high vertical lithostatic loads, while reduced vertical stress in shallow rock favors horizontal compression and thrust-related stress. Fractures in ZK2 are stable, whereas ZK1 contains intervals with high slip potential, which require priority monitoring.[Significance] This work provides shallow in situ stress datasets for Guangdong derived from field measurements, significantly improves hydraulic fracturing interpretation reliability, and offers essential mechanical parameters for near-surface engineering construction and hazard assessment. Furthermore, it demonstrates that shallow crust stress evolution is controlled by mechanisms distinct from deeper tectonic stress fields, highlighting the scientific necessity of shallow stress measurement.