A method for developing and extracting biological trace evidence comprises the following steps: (1) using a biological fluorescent development reagent to process a porous carrier so as to develop biological trace evidence on the porous carrier, wherein a raw material formulation of the biological fluorescent development reagent is, in percent by weight: 0.01%-0.5% of indanedione, 4%-10% of ethyl acetate, 0.5%-1.5% of glycerol, 5%-15.5% of pure alcohol, and 73.5%-90% of petroleum ether; and (2) extracting the biological trace evidence to obtain DNA information of the biological trace evidence. For crime investigators who need to extract DNA evidence, the method enables targeted extraction of physical evidence, thereby greatly reducing workload, and furthermore, the method can also be used to develop and extract obscure or trace evidence, such as a fingerprint on a garment, thereby greatly improving investigation efficiency.