The focus of this work is modelling of droplets collision in turbulent evaporating spray. To predict the collision frequency, two modeling approaches — the O'Rourke's method and the NTC (No Time Counter) method are applied. The Brazier-Smith model is used to predict a possible collision outcome which is either droplet coalescence or grazing collision. The effect of droplet collisions on vapor concentration in turbulent evaporating spray has been demonstrated using the in-house code Fire3D. It has been found that droplet coalescence causes the increase of droplet size which leads to the reduction of the evaporation rate. As a result, neglecting droplet collisions in simulations of a starting spray may cause considerably underestimated vapour concentration along the spray axis.