The present invention relates to the technical field of wireless communication and of mobile communication, and more particularly to a method for spectrum resource allocation and interference avoidance of femtocell in a heterogeneous environment consisting of macro cell and femtocell, and specifically to a spectrum allocation method based on interference suppression and user difference bandwidth requirements. According to the spectrum allocation method based on interference suppression and user difference bandwidth requirements of the present invention, spectrum resource can be allocated reasonably according to the priority level of bandwidth requirements in combination with graph coloring algorithm and chromaticity preference algorithm. In this manner, in-layer interference among femtocells and cross-layer interference among femtocells and macro cells can be effectively suppressed, the difference bandwidth requirements of femtocell users can be satisfied, and the efficiency of frequency utilization and the whole throughput of system can be also optimized to the maximum extent.