Based on the monitored data of soil PH and measured VIS-NIR reflectance on given spots, the relationship between measured reflectance and soil PH was analyzed. Partial least squares regression (PISR) was used to build predicting model of pH value, band ratio, differential and normalization were calculated based on measured VIS-NIR reflectance within 400 – 900 nm. The results showed that band ratio and normalization can effectively enhance the correlations between spectral and soil pH, and interference information was suppressed. Accuracy of the model based on normalized got the best effect, R2 was 0.90, which showed that the band contained most information of soil pH.