Flame-retardant fabric finishing agent and fabric finishing method

The invention relates to the technical field of fabric finishing, and provides a flame-retardant fabric finishing agent and a fabric finishing method. The flame-retardant fabric finishing agent is prepared by adopting a two-step extraction method, and before flame-retardant components in enteromorpha are extracted by adopting an extracting solution b (deionized water), pigments in the enteromorpha are extracted and removed by adopting an extracting solution a (consisting of ethyl 2, 4-decadienoate, ethanol and acetone). 2, 4-decadienoic acid ethyl ester is added into an extracting solution a, chlorophyll and xanthophyll can be promoted to be dissolved out and enter the extracting solution a under the condition that ultrasonic, microwave and other auxiliary methods are not used, pigment extraction and removal are more efficient and thorough, pigment residues in enteromorpha powder obtained after primary extraction are greatly reduced, and correspondingly, the content of the pigment in the enteromorpha powder i