The document describes a method for the determination of chroma in groundwater by platinum-drill standard Colorimetric. It is suitable for the investigation, evaluation, monitoring and utilization of groundwater resources. The minimum detection chroma is 5 degrees, and the measurement range is 5 degrees to 50 degrees. Based on the standard chroma series formulated with potassium chloroplatinate and cobalt chloride, the chroma of water samples is determined by visual Colorimetric. The required reagents include pure water and platinum-drill standard solution, whose chroma is 500 degrees.