If the loan principal: 300,000. Duration: 30 years. According to the benchmark annual interest rate of the People's Bank of China for loans over five years: 4.90% (unchanged), the principal and interest will be repaid in equal amount, and the monthly payment will decrease gradually, such as the first phase: 2058.33, the second phase: 2054.93, and the third phase: 205 1.53, with the decreasing amount of 3.4 per phase.