The black hole candidate system SLX 1746–331 was back to business in 2023, after a long silence of roughly 13 years. An outburst was observed thoroughly by Insight-HXMT and NICER. The outburst is characterized by spectral dominance of the soft state, where the joint Insight-HXMT and NICER spectral analysis shows the temperature dependence of the disk flux follows T~3.98 in and thus suggests that the inner disk reaches to ISCO during almost the entire outburst. By assuming 0.3 LEdd for the peak flux and an inclination angle of zero degree, the lower limit of the compact object hosted in this system is estimated as 3.28±2.14M⊙. We also look into the relation of the disk temperature and disk flux for a sample of black hole systems, and by taking the disk temperature derived in the outburst of SLX 1746–331, such a relation results in a mass estimation of 5.2 ± 4.5M⊙.Finally, the spin of the compact object is constrained to larger than 0.8 with a spectral model of kerrbb.