The performance of normalized throughput in wavelength division multiplexing (WDM) based coherent time-spreading optical code division multiple access (TS-OCDMA) system is studied. The upper bound and lower bound of normalized throughput are obtained with 8 wavelength channels and 127-length Gold code, and with 4 wavelength channels and 511-length Gold code respectively. It is shown that when all simultaneous users are equally allocated to different wavelength channels, WDM+TS-OCDMA has much better performance. However, if there is no central control to allocate wavelength channels equally, WDM+TS-OCDMA system has the in-between performance of normalized throughput.