The asymptotic formula for mean square of the Riemann zeta-function times a Dirichlet polynomial of length T θ is proved when θ < 17/33 and θ < 4/7 for a special form of the coefficient, while for a general Dirichlet L-function, it is only proved when θ < 1/2, without any special better result, by Bauer [2] in 2000. This is due to the additional Dirichlet character contained in the coefficient, which causes error terms harder to control. In this work, we prove a general Dirichlet L-functions has the same results as the Riemann zeta-function. A more general form of the coefficient than one in Conrey [11] is also obtained for the θ < 4/7 case. As an application we obtain that, for every Dirichlet L-function, more than .4172 zeros are on the critical line and more than .4074 zeros are on the critical line and simple.2010 Mathematics Subject Classification. 11M26, 11M06 .