The Gutenberg-Richter (GR) b value is a proxy for crustal stress that has been widely applied in earthquake prediction, regional stress analysis and earthquake physics investigation. Following the 2019 Mw 7.1 Ridgecrest earthquake sequence, a large number of aftershocks were well documented along the earthquake faults. We analyzed these aftershocks based on the GR law for the spatiotemporal b value distributions within the fault zone in three dimensions. The results show that the b values are homogeneous in space at a low level of ~ 0.6 immediately after the mainshock, while they increase rapidly within 3 months to ~ 1.0, which was thought to be an average level for California in the interseismic period. Meanwhile, in the first few weeks after the mainshock, the distribution of the b values along the faults is heterogeneous, where the recovery rates of the b values on individual fault cells vary dramatically along both the strike and dip. Considering significant postseismic geodetic observations, the afterslip processes along the faults may be responsible for the time-dependent variation in b values. Given that frictional sliding is a key mechanism for afterslip, the b values could then have potential for fault frictional properties, which deserve special care in the future. [ABSTRACT FROM AUTHOR]