Abstract: The B-L（Bézier-Like） curves over the trigonometric function space Φ₇=span{1，sint，cost，cos2t，sin3t，cos3t，sin4t，cos4t}and Φ₈=span{1，sint，cost，sin2t，cos2t，sin3t，cos3t，sin4t，cos4t} are constructed，the explicit expressions of the B-L curves are presented.Then some properties and applications of this kind of curves are discussed.Cardioid，elliptic curves，circular arc，ellipsoid，sphere without rational form are precisely expressing，and circular helix is approximated by the B-L curves.Examples are given to illustrate the convenience and validity in model design.

Key words: trigonometric polynomial, trigonometric basis, B-L curves and surfaces

摘要： 在三角函数空间Φ₇=span{1，sint，cost，cos2t，sin3t，cos3t，sin4t，cos4t}和Φ₈=span{1，sint，cost，sin2t，cos2t，sin3t，cos3t，sin4t，cos4t}中构造了B-L（Bézier-Like）曲线，并给出其显式表达式。进一步讨论了该曲线的若干性质和应用，给出了不需要有理形式的心脏线、椭圆（圆）弧等的B-L曲线精确表示，椭球（球）面的B-L曲面精确表示，以及圆柱螺线的B-L曲线逼近表示。通过实例说明在造型设计方面使用简便且有效。

关键词: 三角多项式, 三角基, B-L曲线曲面