The invention relates to a concrete mixer with good stirring effect. The concrete mixer comprises a stirring chamber and a base and further comprises a heat preservation mechanism and a stirring mechanism. The heat preservation mechanism comprises a water tank, a heat preservation pipe, a high pressure water pump, a first driving assembly and a heat preservation assembly. The heat preservation assembly comprises a first gear, a second gear, a first sleeve, a first baffle, a second baffle, a second sleeve, two support sleeves, two second connecting rods and two first connecting rods. The stirring mechanism comprises a second driving assembly, a third driving assembly, a support rod, a strengthening sleeve, a connection shaft, two sliding sleeves, a rotary rod and two stirring rods. According to the concrete mixer with good stirring effect, by means of the heat preservation mechanism, concrete can be heated, thus the influence of low temperature on concrete quality is reduced; by means of the stirring mechanism, the stirring rods can move along the rotary rod while being driven to rotate; and thus the stirring range of the stirring rods is enlarged, and the stirring quality of the concrete mixer is improved.