A method for preparing analogues of C1,C24-dihydroxy-vitamin D is disclosed. Especially the method for preparing calcipotriol and tacalcitol from a starting material of Vitamin D2 is disclosed here. Calcipotriol (compound 1(a)) and tacalcitol (compound 1(b)) can be synthesized by the method of the present invention. Moreover, only nine steps are needed for the synthesis of calcipotriol using the method. Likewise, only ten steps are needed for the synthesis of tacalcitol by the present method. Hence, the present method, with less process steps and higher yields, represents an improvement over the conventional methods.