【Objective】 Soil pH is a crucial indicator of arable land quality. Therefore, precise and rapid measurement of soil pH is essential for the implementation of digital agriculture. 【Method】 In the present study, pH levels of the black soil in the Liaohe and Songnen plains were determined in situ using a self-developed portable soil multi-parameter rapid detection instrument (SHMI2000). The results were compared to those obtained in the laboratory using the potentiometry method (HJ 962-2018). 【Result】 (1) The laboratory observations showed that surface and subsurface soil pH values ranged from 4.04 to 10.09, and 4.01 to 10.06, respectively. The mean values were 6.13 and 6.47, and the variation coefficient values were moderate at 19.64% and 18.37%, respectively. Also, the study also revealed that the soils in the southwest black soil area were predominantly alkaline, whereas the soils in the east (Sanjiang Plain), north (Songnen Plain), and south (particularly in the Southern Heilongjiang, Jilin, and Liaoning Provinces) were acidic in nature.(2) The Pearson correlation analysis showed a strong relationship (correlation coefficient of 0.81, P=9.11×10^-52) between pH values obtained in situ and the laboratory. (3) The correlation coefficient increased to 0.93 after the moving average process, using 0.2 pH units as step size.【Conclusion】 Therefore, the SHMI2000 instrument can accurately and reliably acquire black soil pH values in situ.