Six pairs of Stokes-anti-Stokes lines of stimulated four photon mixing in a multimode fiber with GeO2+P2O5 doped silica core are simultaneously recorded. A continuum band generated jointly by SFPM and stimulated Raman scattering is obtained in the spectral range 540-640 nm. On the basis of two different experiment results for 20 m and 200 m fiber, the mechanism of competition and transformation between SFPM and SRS are analyzed in some detail.