U Minh Thuong National Park is a key site for wetland biodiversity conservation in Vietnamese Mekong Delta. This paper outlines a field experiment carried out in U Minh Thuong National Park in the dry season 2019. The study aimed to compare methane emissions and related physicochemical soil and water parameters between the Peat swamp forest and Melaleuca forest. The results show that both water and soil parameters at 8 examined sites in Melaleuca forest and Peat swamp forest fluctuated highly over the sampling intervals. The average hourly C-CH4 emission rates in Melaleuca forest (26.58 mg/m2/h) was higher than that in Peat swamp forest (21.18 mg/m2/h). Generally, water level and redox potential were important factors regulating emissions of methane gases. The Eh values were all negative values, ranged between −196.5 ± 22.75 mV and −27.75 ± 15.37 mV, indicative of high electron activity and intense anaerobic. Peat swamp forest’s soil had relatively higher organic matter, CEC, TN and TP values than Melaleuca forest’s soil. The COD values fluctuated between 197.3 ± 51.78 mg/L and 396.8 ± 25.77 mg/L, indicative of organic pollution of surface water. It is suggested shorter time measurement (at least twice a day) of methane emission for more accurate evaluation.