The pure Phragmites australis marsh in northwest Shanyutan of the Min River estuary was selected as the study object. The effects of enhanced nitrogen (N) load on decomposition and nutrient release of P. australis litters were determined by field N load decomposition experiment which included four N load levels:NL0 (no N load treatment, 0 g N m^-2 a^-1); NL1 (low N load treatment, 12.5 g N m^-2 a^-1); NL2 (medium N load treatment, 25.0 g N m^-2 a^-1) and NL3 (high N load treatment, 75.0 g N m^-2 a^-1). Results showed that the decomposition rates of P. australis litters generally followed the sequence of NL2 (0.00284 d^-1) > NL1 (0.00263 d^-1) > NL0 (0.00257 d^-1) > NL3 (0.00250 d^-1), indicating that the low load level and medium load level generally promoted the decomposition of detritus while the high load level inhibited its decomposition, which was primarily related to the great alterations in substrate quality and pH during decomposition in different N load treatments. The total carbon (TC) contents in decomposing litters of different N load treatments showed distinct fluctuations during decomposition. By comparison, the total nitrogen (TN) or total phosphorus (TP) contents in detritus in the four treatments decreased abruptly at the early stage (0-30 days), after which the values showed different fluctuations. Thereinto, the total nitrogen (TN) contents in detritus generally showed an increasing trend, while the total phosphorus (TP) contents in decomposing litters showed slight fluctuations. Stocks of C, N, and P in decomposing litters in different N load treatments generally evidenced the export from detritus to the environment. Litter mass remaining was a common factor influencing the net release of C, N and P from decomposing litters in different N load treatments. However, the release amounts of C, N and P from detritus primarily rested with the alterations of substrate quality (e.g., C/N, C/P, N/P) and key environmental variables (e.g., pH, EC) which were caused by different N load levels. The study found that the accumulation and release of detritus nutrients have changed significantly under the background of effects of N load enhancement. In the Min River estuary, elevation of N load levels would inhibit the release of C and N from P. australis litters as a whole, but it might show obvious stimulation on P release during the middle and late stages (90-240 days) of decomposition.