In order to study the effects of diesel injection pressures and methanol substitution rates on the flame shapes, reaction zone properties and distribution of reaction intermediates in the development of methanol–diesel dual direct injection flame, the visualization of methanol–diesel dual direct injection flame was studied by using OH^* chemiluminescence and flame self-luminescence high-speed synchronous imaging techniques on constant volume combustion chamber（CVCC）. The results show that when the injection pressure is low, the atomization is poor, and some oil droplets are fully burned after colliding with methanol. When the injection pressure is high, the injection pulse width is shorter and the combusting effect is weaker. The selection of methanol substitution rate needs to balance combustion performance and exhaust emissions, which also has an important impact on the shape of the dual direct jet flame and the distribution of diesel fuel in the flame. When the methanol substitution rate increases from 60% to 90%, the peak heat release rate decreases by 33.2%.