The sum frequency , difference frequency and corresponding cascading nonlinear effect were reported with 800 nm and 400 nm femtosecond light beams satisfying the phase-matching condition in BBO crystal. We obtain sum-frequency 267 nm and difference-frequency 800 nm waves simultaneously, taking account of phase matching of sum frequency and difference frequency. The laser pulses are with 10 Hz repetition rate, 800 nm central wavelength, 60 fs pulse width and 7 mm spot diameter. The 10 mJ output energy of the Ti∶sapphire regenerative amplifier are split into two beams, and 70% energy is frequency doubled to 1.45 mJ of 400 nm by the first nonlinear crystal BBO and then injected into the second one with 3 mJ, 800 nm laser beam. For both of them there exists a small amount of detuning. When the new pulses mix frequency with input waves further, one-dimensional array of more than 10 beams including ultraviolet, visible bands can be observed. The mechanism and influencing factors of the input light intensity, chirp, relative time delay on the cascading nonlinear effect are investigated in details.