Currently, five BDS-3 experiment satellites are transmitting both BDS-2 signals and new signals for users. They are equipped with high-precision rubidium or/and passive hydrogen maser clocks. In view of the inconsistency of BDS-3 experiment satellites signals received by iGMAS and MGEX network, the experiment to determine BDS-3 orbits is carried out by the step by step method through one year. In order to improve the efficiency and avoid the inverse anomalies caused by too large matrix dimension in the inversion process, the normal equation matrix is decomposed by Cholesky. In this paper, the internal accuracy of BDS-3(C31/C32/C33/C34) satellites orbit and clock offset is evaluated by overlapping arcs, and the average values in one year are 36.5 cm/38.4 cm/44.1 cm/48.8 cm and 2.27 ns/2.40 ns/1.88 ns/1.87 ns respectively. In addition, satellite laser ranging (SLR), as an important external inspection tool, has been widely used in satellite orbit accuracy assessment. Using SLR to evaluate the orbit outside accuracy, and the average values of one year is 51.4 cm/40.2 cm/62.9 cm/82 cm. Finally, the precision of BDS-3 satellites broadcast-clock offset and broadcast-orbit is evaluated by BDS-3 precise ephemeris, and the SLR observation data is taken as the external inspection tool to evaluate the orbits. The results show that the BDS-3 experiment satellite broadcast-clock accuracy is better than 40 ns, and the broadcast-orbit accuracy is about 1 m.