1. Conceptual difference: Pay-as-you-go system refers to a pension financing mode that collects pension insurance premiums in the current period for the purpose of paying retirees' recent pensions. Fund accumulation system refers to the mode of raising funds through self-vertical reserve and accumulation of insurance premiums, and using the accumulated funds to pay pensions for the insured.

2. Operating cost difference: the operating cost of pay-as-you-go system is low, and the pension payment under the system directly uses the insurance premium collected in the current period without accumulating funds. The operation cost of fund accumulation system is high, so it is necessary to establish and maintain pension funds, including the expenses of fund investment management, risk control and operation management.