Abstract: High solids loading pneumatic conveying of pulverized coal was achieved in a new pneumatic conveying system where solid/gas mass flow ratio reached 200—580 kg•kg^-1.Operation conditions, including transport pressure,gas volume and pipe diameter were specially designed for the conveying system with pipelines of 15 mm, 20 mm, 32 mm(I.D.) respectively.The effects of different operation conditions on the characteristic parameters, i.e. mass flow rate, solid/gas mass flow ratio and superficial gas velocity, as well as the relationships within the operation conditions themselves, were investigated in the experiments.It was found that under a higher pressure a greater supply of gas was needed, which resulted in greater conveying capacity.However,solid/gas mass flow ratio declined dramatically when solid mass rate increased.The analysis of the experiment also revealed that pipeline diameter was actually the crucial element which brought about great difference in conveying capacity in contrast to the results from the change of operation pressure.Some empirical expressions were finally established which were capable of describing the relationship between the aforementioned parameters and again pipe diameter played an important role.The expressions additionally revealed that gas supply surged with the increase of pulverized coal mass flow rate.The quantitative relations of the parameters might be system-dependent, but this paper presents useful information and approach to pneumatic conveying.