RTK-GPS is one of the most accurate positioning methods that gives centimeter-level accuracy and is used in various fields in agriculture and environment. However, the high cost of this RTK-GPS system is a big obstacle for applications such as precise farming and environmental monitoring in the Mekong Delta. This study is to evaluate the application of RTK-GPS with low-cost NEO-6P and LEA-6T GPS receivers and RTK-GPS library. Experiments with static and kinematic positioning modes were conducted. Experimental results showed that low-cost RTK-GPS systems are promissing for applications in which relative positioning error of 0.3 meter is acceptable.