The appearance of large-scale low earth orbit satellite constellation puts forward better requirements for the ground TT&C system. So many contries focus on measurement and network system. In this paper, the access problem of satellite TT&C network system is studied. Firstly, the development history of traditional low orbit satellite constellation and the demand background of multiple access technology are summarized. Then, based on the analysis of traditional access such as CSMA and TDMA, an adaptive access scheme is proposed, which makes the measurement and control system have nice performance when the load is high or low. In this paper, the advantages of the adaptive access scheme in system delay, throughput and channel utilization are verified by simulation.