Abstract:The author studies on rule in change of trunk shape structure for pulp forest of Phyllostachys pubescens Mazel ex H.de Lehaie with result showing length of inter-joint,perimeter,wall thickness and inter-joint of Phyllostachys pubescens Mazel ex H.de Lehaie link with parabola and straight line individually,finds they exist obvious relevant relationships.Different sea level height posses significant effect to joint length,perimeter of Phyllostachys pubescens Mazel ex H.de Lehaie.