The Haseman-Elston model is an important method for linkage analysis of quantitative traits. In this paper use of trait products of sib-pairs as the dependent variable to establish its linear relationship with the marker's IBD score is derived following the original proof procedure of Haseman and Elston. Based on the three currently used Haseman-Elston models(squared trait difference, squared trait sum and trait product), a combination test approach is proposed for joint test of linkage between a quantitative trait and a marker. This method can be easily extended to other transformed Haseman-Elston models.