In this work, we report the structure and magnetic properties of DyFe0.6Mn0.4O3, which crystallizes in orthorhombic perovskite structure with a space group of Pnma. For DyFe0.6Mn0.4O3, a spin reorientation transition, from the canted antiferromagnetic (AFM) state to a collinear AFM state, is found to occur around 310 K, which is remarkably higher than the corresponding transition in DyFeO3. This will greatly facilitate its practical electronic applications near room temperature. More importantly, the AC susceptibility reveals that its frequency-dependent spin reorientation temperature decreases with increasing frequency, which is totally opposite to that of a spin glass. The relaxation time of this process is also much larger than conventional spin glass. The possible mechanism of this distinctive process is explored, which is based on the characteristic feature of spin reorientation for DyFe0.6Mn0.4O3.