This paper studied the KdV equation with timedependent coefficients and forcing term and the coupled KdV equations with timedependent coefficients by using soliton ansaze. Firstly, the equation was converted to homogeneous equation by using a variable transformation. Then, by assuming the soliton solutions to be the form of sech function, and with the help of Maple software, the complicated and tedious calculations were performed, and the conditions of existence of solitons and soliton solutions were obtained. The results show that the calculation of soliton ansaze is simple and can obtain bright soliton solutions.