Abstract: Uniform parametric sampling often provides low-quality sampled points and leads to unsatisfactory B-spline fitting curves.To resolve this problem,a uniform sampling method is proposed for spatial curves using intrinsic geometric quantities,so as to obtain a prescribed number of representative points.Firstly,the characteristic function is defined as a weighted combination of arc length,curvature and torsion,and it can more closely match various curve shapes by adjusting the combination parameters.Then an adaptive sampling method is proposed for spatial curves using intrinsic geometric quantities,which iteratively generates sampled points until a given distance threshold is satisfied.By using the evaluation indicators of maximum absolute error and root mean square error,numerical examples are implemented when comparing with uniform sampling in arc length and uniform sampling in the average of arc length and curvature.The experimental results show that the proposed method remarkably improves sampling quality and B-spline fitting results.