Aim\ To study the estimation of parameters in the linear model with constraint. Methods The linear model of mixed coefficient is turned into a generalized linear model
and the relevant methods of linear models is used. Results\ An estimate of fixed coefficient
expectation and variance of random coefficient with constraint in the linear model of mixed coefficient is given. At the same time
the nature of the estimate is discussed. Conclusion\ This theory and method will be universally available to the estimate of parameters which can be turned into linear models.