In order to obtain organic electroluminescent diodes (OLEDs) with low driving voltage,long lifetime and high light efficiency,a series of novel n-type host materials DTRz,DBTRz and DCNTRz based on 1,3,5-triazine and 7,7-dimethyl-5,7-dihydroindolinazol [2,1-b] carbazole are introduced in this paper. First,their electrochemical properties,photophysical properties and thermal stability were studied,and DFT calculations were performed. The experimental and computational analysis results show that DTRz,DBTRz and DCNTRz have higher triplet energy levels (2.83,2.71,2.72 eV),higher decomposition temperatures (411,499,419 ^oC). Then,the photoluminescence spectrum was studied after mixing with P-type host NBPBC (1∶1),and based on this,the device was fabricated with Pt(BBP) as the guest dopant. The analysis of the device results shows that the DCNTRz∶NBPBC-based device has a turn-on voltage of 2.1 V,a maximum external quantum efficiency of 14.3%,a maximum brightness of 221 589 cd·m^-2,a current efficiency of 46.5 cd·A^-1 at 1 000 cd·m^-2,and a maximum power efficiency of 45.7 lm·W^-1.In particular,the device lifetime (LT95) reaches 282 h at 4 000 cd·m^-2. 54% higher lifetime than DTRz∶NBPBC-based devices. A green OLED with excellent performance such as low turn-on voltage,high lifetime and high luminous efficiency is realized.