Abstract: The female gametophyte development in Cattleya was studied by the method of paraffin cut. The results showed that the placental growth and ovule development did not initiate until pollination. After successful pollination, the ovule primordium begins to grow. The ovule is anatropous with 2 integuments and one-layered nucellus around the megaspore mother cel1. The mature embryo sac consists of 8 nuclei. The interval between pollination and the mature embryo sac is about l12 days. The advanced development of out integument might be a reason causing the abortion of embryo.