On the basis of the nonlinear schrodinger equation with the perturbation, the formulas are obtained diretly from the approximative 2 soliton solution to describe the soliton interaction in the practical optical fiber soliton communication. These formulas show that the soliton interaction in practical communication not only depends on their relative phase difference but also on the changes of their energy and velocity difference with the transmission distance. The extended soliton interaction theory can be applied to discuss generally how the perturbations impose effects on the interaction. And the extended theory also can give explanations to the experimental phenomenon about the short-range interaction and long-range interaction reported in Optical letters in 1987, 1989, 1990.