Abstract: To determine economical applicability of pipeline transportation (PNG), LNG road tanker and CNG road tanker for natural gas transportation, cost analysis are performed for these three modes and empirical equation for transportation cost of natural gas per unit volume is established. Based on the empirical equation, unit costs for the three transportation modes are reviewed to obtain critical curves for economical transportation of these modes. These curves reflect the most economical transportation mode under different distances and scales directly, i.e., ①CNG road tanker is more suitable for transportations with minor scales and short distances, with maximum capacity of 16×10⁴ m³/d and maximum distance of approximately 300 km, ②only for transportation distances over 236 km, LNG road tanker has economical performance superior than those of CNG and PNG, ③PNG road tanker has the most evident scale effect with the fast reduction in transportation cost per unit volume with the scale of transportation.