I propose a simply method to estimate the regression parameters in qua
si-likelihood model. My main approach utilizes the dimension reduction
technique to first reduce the dimension of the regressor X to one dim
ension before solving the quasi-likelihood equations. In addition, the
real advantage of using dimension reduction technique is that it prov
ides a good initial estimate for one-step estimator of the regression
parameters. Under certain design conditions, the estimators are asympt
otically multivariate normal and consistent. Moreover, a Monte Carlo s
imulation is used to study the practical performance of the procedures
, and I also assess the cost of CPU time for computing the estimates.