In the field of compressed sensing, the restricted block $\ell_1-\ell_2$ minimization model can recover the block sparse vector well. When solving the restricted block $\ell_1-\ell_2$ minimization model, it is often transformed into a unrestricted $\ell_1-\ell_2$ minimization model, and then the convex algorithm is used to solve the new model. Experiments have shown that this method is effective, but the theoretical results of the unrestricted $\ell_1-\ell_2$ minimization model being able to recover block sparse vectors have not yet been established. The main task of this paper is to establish sufficient conditions for the unrestricted $\ell_1-\ell_2$ minimization model to recover block sparse vectors based on the RIP condition, and to demonstrate the influence of parameter $\lambda$ in the unrestricted $\ell_1-\ell_2$ minimization model on the recovery of block sparse vectors through experimental methods.\\