The invention relates to a valley electricity analysis-based electricity meter dynamic assessment system and method, and solves the problems that manual meter reading is long in cycle and hysteretic in result, a general electricity meter only can obtain a total electric quantity and cannot obtain electricity usage states of electric appliances, and the electricity usage of the electric appliancesis not subjected to energy conservation analysis in the prior art. The system comprises an electricity meter end, a cloud server and a user end; the electricity meter end comprises a collection unit and an electricity meter unit; and the cloud server comprises a computing unit, a storage unit and an identity verification unit. According to the method, an assessed value of energy consumption of each day is calculated by adopting grey correlation analysis, and the energy conservation analysis is performed according to the assessed values. The problem that a general electricity meter system onlycan simply display an energy consumption value is solved, so that a user can detailedly know specific energy consumption of electric equipment; and the electricity usage state of each day can be subjected to the energy conservation analysis, so that the electricity usage state is clear to the user, the user can timely adjust electricity usage time or an electricity usage quantity according to an energy conservation state of electricity usage, and a better energy conservation effect is achieved.