By means of symbol operation of Matlab and the convergent condition of the linear muhistp method formula, the authors attained the well posed convergent formulas directly for all linear 2-step methods. Some convergent formulas are gotten after screening and the fraction coefficients, errors coefficients, orders and intervals of absolute stability are calculated. Then figure of region of absolute stability of the absolute stability formula is drawn by means of root locus method. The performance of those formulas simply is analyzed. One new A - stable formula of linear 2-step methods of order 2 is derived and proved.