We have grown a YCrO3 single crystal by the floating-zone method and studied its temperature-dependent crystalline structure and magnetization by x-ray powder diffraction and PPMS DynaCool measurements. All diffraction patterns were well indexed by an orthorhombic structure with space group of Pbnm (No. 62). From 36 K to 300 K, no structural phase transition occurs in the pulverized YCrO3 single crystal. The antiferromagnetic phase transition temperature was determined as T N = 141.58(5) K by the magnetization versus temperature measurements. We found weak ferromagnetic behavior in the magnetic hysteresis loops below T N. Especially, we demonstrated that the antiferromagnetism and weak ferromagnetism appear simultaneously upon cooling. The lattice parameters (a, b, c, and V) deviate downward from the Grüneisen law, displaying an anisotropic magnetostriction effect. We extracted temperature variation of the local distortion parameter ". Compared to the "value of Cr ions, Y, O1, and O2 ions show one order of magnitude larger "values indicative of much stronger local lattice distortions. Moreover, the calculated bond valence states of Y and O2 ions have obvious subduction charges.