The present invention relates to a liquid fuel blended by dissolving crude pentane into the heavy oil with different proportions, and applied to different combustion system respectively; the fuel thus formed is easily dissolved, volatilized, atomized and vaporized into fine vapor articles, so it will burn completely to not only increase the heat value but also reduce the pollution without producing the dense smoke like common heavy oil combustion furnace. In addition, alkanes with low price, low octane value and high volatility substitute or blend with the crude pentane to become a liquid fuel having suitable initial boiling point, viscosity and fluidity as well as low price and low pollution, which is much better than common diesel oil.