Based on the generation mechanism of spectral amplitude code(SAC) and the technique of frequency swept coherent detection,we set up an optical label switching system which can detect the 156 Mbit/s label.After adding 40 Gbit/s intensity modulated(IM) payload,we research the transmission performance of the label on the condition of various local oscillator(LO) line width,power and spacing between label and payload after transmission of 0 km,40 km and 80 km.At the same time,we research the bit error rate(BER) of the payload on the condition of various received optical power(ROP),optical signal to noise ratio(OSNR) and spacing between label and payload.The results suggest that the label eye height(EH) can reach about-0.6 dB after transmission of 80 km and when the bit error rate(BER) of payload reaches 10-9,the ROP and OSNR are-17.8 dBm and-14.5 dB,respectively.