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<jats:title>Abstract</jats:title> <jats:p>Impurity transports in two neighboring discharges with and without electron cyclotron resonance heating (ECRH) are studied in the HL-2A tokamak by laser blow-off (LBO) technique. The progression of aluminium ions as the trace impurity is monitored by soft x-ray (SXR) and bolometer detector arrays with good temporal and spatial resolutions. Obvious difference in the time trace of the signal between the Ohmic and ECRH L-mode discharges is observed. Based on the numerical simulation with one-dimensional (1D) impurity transport code STRAHL, the radial profiles of impurity diffusion coefficient <jats:italic>D</jats:italic> and convective velocity <jats:italic>V</jats:italic> are obtained for each shot. The result shows that the diffusion coefficient <jats:italic>D</jats:italic> significantly increases throughout the plasma minor radius for the ECRH case with respect to the Ohmic case, and that the convection velocity <jats:italic>V</jats:italic> changes from negative (inward) for the Ohmic case to partially positive (outward) for the ECRH case. The result on HL-2A confirms the pump out effect of ECRH on impurity profile as reported on various other devices.</jats:p>