The invention relates to the field of code stream coding, in particular to a code stream coding method and device for code stream receiving equipment. The method comprises the following steps: receiving an externally-input original code stream; decoding code stream data of each IDR (Instantaneous Decoding Refresh) frame in the original code stream; selecting an IDR frame to serve as a current long-term reference frame; calculating a first PSNR (Peak Signal to Noise Ratio) between YUV data obtained after decoding the IDR frame and YUV data obtained after decoding the current long-term reference frame; when the first PSNR is greater than a first threshold value, performing P-frame coding on the YUV data obtained by decoding the IDR frame by taking the current long-term reference frame as a reference; and replacing P-frame code stream data with code stream data corresponding to the IDR frame. Through adoption of the method and the device, a long-term reference coding code stream is obtained; the process is simple; the image quality is ensured and meanwhile coding rate can be lowered effectively; and moreover, hardware does not need to be modified. The method and the device can be seamlessly applied to current code stream receiving equipment.