The invention discloses a system for implementing beam forming for a single user is, in the system, a null widening calculation unit is for calculating the first beam forming weight corresponding to the first detection threshold and the second beam forming weight corresponding to the second detection threshold by using a null widening algorithm according to the input first detection threshold and second detection threshold; a beam forming unit is for implementing beam forming according to the first beam forming weight and second beam forming weight respectively. The invention further discloses a method for implementing beam forming for a single user, and the method includes: calculating the first beam forming weight corresponding to the first detection threshold and the second beam forming weight corresponding to the second detection threshold by using a null widening algorithm according to the input first detection threshold and second detection threshold; and implementing beam forming.