Optical code division multiplex access (OCDMA) transmission system experiment based on spectral splicing is demonstrated. Different users are distinguished by the different free spectral range (FSR) of the tunable Fabry Perot cavity of the encoder/decoders. The influence of the multiple access interference (MAI) on the system performance is analyzed. The performance of the transmitter, the optical channel and the encoder/decoder is discussed. The BER measurement is also realized. The test results show that the bit error rate is better than 10 -9 after transmission of 11 km simple mode fiber with the access rate of 155 Mb/s and the MAI value 30 times higher than received optical power. This system is a possible solution for the future all optical access system for its lower cost and simple structure.