Electric heat tracing pre-curing is a simple and efficient method to ensure the curing temperature and strength development of ready-mixed concrete in cold weather. The research analyzed the effects of pre-curing temperature and aging on the compressive strength of a high slump C30 normal concrete. Tests of 7 d constant negative temperature (-5 ℃, -10 ℃, -15 ℃) once-freezing to standard curing pretreatment test were reported. According to the definition of critical strength, the reasonable critical strength values and pre-curing time under the electric heat tracing pre-curing treatment were acquired. The results show that concretes pre-cured by electric heat tracing subjected to high temperatures attain higher compressive strengths than concretes subjected to normal temperature. Nevertheless, the pre-curing temperature should be controlled at 30 ℃, because the rate of strength development and R-7+28 (compressive strength of negative temperature curing for 7 d and then standard curing for 28 d) are reduced at higher pre-curing temperatures. When the pre-curing temperature is 30 ℃ and the hardening temperature is not lower than -15 ℃, the pre-curing time is between 36 h and 48 h. Under the hardening condition of constant negative temperature (-5 ℃, -10 ℃, -15 ℃), the critical strength of concrete pre-cured with electric heat tracing is in the range of 6.6 MPa to 17.8 MPa, which is 22.0% to 59.3% of the standard value for the compressive strength of concrete cubes. This paper aims to compare the influence of electric heat tracing pre-curing treatment on the mechanical properties of common concrete and to guide the relevant engineering applications.