Trivalent chromium electroplating liquid and electroplating method

The invention relates to trivalent chromium electroplating liquid and an electroplating method, and belongs to the field of electroplating. Each liter of electroplating liquid comprises the following components: any one or several of chromium potassium sulfate, chromium sulfate and alkaline chromium sulfate of 20-80 g, complexing agent of 1-10 g, wetting agent of 0.5-5.0 g, stress eliminating agent of 0.1-0.5 g, and electric conducting salt of 30-150 g; and the complexing agent is polycarboxylic acid or polycarboxylic acid containing hydroxyl. When the electroplating liquid is used for electroplating trivalent chromium, the defect of cracking of a plating layer above 35 microns can be prevented. The uniform and compact plating layer of 50-150 microns can be obtained; and the hardness of the plating layer is 850-1000 HV. After the plating layer is heated by 5 min at 200 DEG C, the hardness reaches 1600-2000 HV.