Abstract: To investigate the effect of ODEA on the microscopic morphology and rheological properties of on-site mixed emulsion matrix, four groups of samples were prepared by compounding Span-80 with different mass fractions of ODEA. The microscopic morphology and rheological properties of the samples were characterized using an optical microscope, a laser particle size analyzer and a rotational rheometer. The results show that with the increase of ODEA mass fraction, the average particle size and the dispersion degree of internal phase droplets of the on-site mixed emulsion matrix decrease first and then increase. When the ODEA content is 1 wt%, the sample has the smallest average particle size, the most uniform particle size distribution and the highest detonation velocity. The addition of ODEA improves the viscosity, storage modulus and cohesion of the composite system samples. Within the experimental temperature range, all four groups of samples can meet the pumping requirements. Compared with the single Span-80 system, the sample with 1 wt% ODEA has the strongest elastic recovery capacity under external force and the best shear stability. This study provides relevant experimental basis for the research on adding small-molecule alkanolamide co-emulsifiers into the formulation of on-site mixed emulsion explosives.