A colorimetric method of new mixed indicator with a wide range and clear changes of colour for soil pH values has been studied. This method was compared with electrometric method using more than eighty soil samples from different parts of China. The results obtained from the two mothods were well agreed and their maximum variation was about 0.3 pH unit. Twenty-two soil samples of various main soil types were examined for pH by different workers, the average deviation was also less than 0.3 pH unit.