Abstract: Constructing an electricity market system for new power system is not only an inevitable requirement of energy and electricity transition but also an important route to achieving the goal of “carbon emission peak and carbon neutrality”. Based on the comprehensive analysis of the changes and challenges brought to power systems by the structural changes of the new power system, a multi-dimensional collaborative electricity market system for the new power system is built from the goals, time, space, values, and entities. Focusing on the five key issues including the multi-goal collaboration of safe supply guarantee, low-carbon transition and economy, the multi-time collaboration of medium-and long-term, spot, and real-time operation, the multi-spatial collaboration of multi-layer national unified electricity market, the multi-value collaboration of security, green and economy, and the multi-entity collaboration with the rapid development of emerging market entities, the concept and core mechanism for the multi-dimensional collaborative market design are proposed. Finally, the implementation route and suggestions for constructing a national unified electricity market are given.