The present invention relates to the technical field of decoding, in particular to a decoding method, storage device and decoder suitable for SOP packets of the USB-PD protocol. Described a kind of decoding method applicable to the SOP packet of USB-PD protocol, comprises the steps: after Preamble is received correctly, starts setting f, and b starts counting simultaneously; If the first K-code is received correctly, c counter adds 1 ;If the first K-code is not received correctly, set h to 1 when b>5; if a K-code packet matching event occurs when b<=5, then set d to 1; if 8<=b< =10 and h=1 when a K-code packet matching event occurs, set e to 1; when d=1, correct b to 5; when e=1, correct b to 10; when b=20 , set g to 1; when d=1 or e=1 or b=5, 10, 15, and 20 in the case of K-code packet matching, add 1 to c respectively; perform sop decoding when c>=3 ; Sop decoding result stored in j. Through this technical solution, the entire sop package can still be completely decoded in the case of any one K-code error or the last preamble error in a total of four K-codes.