Using phase control between four-wave mixing (FWM) and six-wave mixing (SWM) channels in a four-level atomic system, we demonstrate temporal and spatial interferences between these two nonlinear optical processes. A Efficient and coexisting FWM and SWM signals are produced in the same electromagnetically induced transparency window via atomic coherence. A The temporal interference has a femtosecond time scale corresponding to the optical transition frequency. ASuch studies of intermixing between different order nonlinear optical processes with a controllable phase delay can have important applications in high-precision measurements, coherence quantum control, and quantum information processing.