To realize uniform and good blending by a simple method by blending a liquefied petroleum gas with a vaporous natural gas stream and combining the mixed stream with a liquefied natural gas stream. SOLUTION: This invention provides a method and an equipment for uniformly blending a natural gas(NG) with a liquefied petroleum gas-(LPG) by providing the first blending section 1 for bending a vaporous NG with LPG to form a mixed stream and the second blending section 2 for combining the mixed stream with LNG. It is desirable that the section 1 is a Venturi mixer. The LNG is sucked into the part where the flow rate of the NG stream is high and is dispersed on the form of misty liquid drops o establish a uniform blended state. At the section 2, the NG liberates its sensible heat and latent heat to cause the LNG to boil. As result, a turbulent flow effecting violent agitation occurs and subsides during the transfer into the downstream of form a steady liquid phase comprising LNG having an adjusted calorific value.