A necessary and sufficient condition for the unbiasedness of Balanced LS Estimation is gained, and for the given L, t can be chosen to make the MSEM of the Balanced LS Estimation less than that of OLS Estimation.

• 给出了平衡LS估计为无偏估计的充分必要条件；对于给定的L；适当地选择参数t可使平衡LS估计的均方误差矩阵小于OLS估计的均方误差矩阵.