A new analytical method based on chemical reaction heat-induced laser beam deflection is presented in this paper, The basic theory of the method is discussed. Dependence of the signal of laser beam deflection on the determination concentration and the effect factors have been investigated, The method is applied to the determiation of following reactions: neutralization , oxidation-reduction, complexing, precipitation and domperidone in motilium tablet with satisfactory results. It is shown that the method can be used widely to the studies on analytical chemistry, solution chemistry, biological chemistry, and thermodynamics.