Abstract: The exploitation of mineral resources is vital to national security and the economy, and with the gradual decline of shallow mineral resources, deep mining has risen to the level of a national strategy. Backfill has gradually become the preferred method of underground mining due to its advantages such as high safety and low impact on the surface environment. Determining the reasonable strength of the backfill is the key to solving the problem of balancing the safety and economy of backfill mining, and it is the core issue for the successful application and healthy development of backfill mining technology. The influence of factors such as cementitious agents, lime sand ratio, backfill aggregates, curing environment, and contact surface characteristics on the backfill strength are sorted out. The backfill strength design methods such as empirical analogy, mechanical model, numerical analysis, and artificial intelligence are summarized. The current research status of backfill strength requirement are summarized, and new ideas suitable for calculating the deep backfill strength requirement is proposed. It aims to improve the calculation theory of deep backfill strength demand, optimize the backfill strength design, and promote the research and application of deep metal mine backfill mining.