Abstract: In order to improve three-dimensional model's precision of rectangle-circ1e variational connector and make modeling processes simpler, this paper introduced a general coordinate algorithm based on analytic geometry.The detailed modeling process using loft method and the algorithm above is described.A development drawing method and detailed processes are presented as well.For manufacturing rectangle-circ1e variational connector sheet metal according with design dimensions, a rule is demonstrated to deal with the thickness while drawing a development.Through examples, it can be shown that the algorithm is easy to programming and performs efficiently.Resultsalso reveal that the algorithm is universal.The modeling method is reliable and it makes automatic development drawing practical.