Context : The intermediate-mass binary pulsars ( IMBPs ) are characterized by relatively long spin periods ( 10 - 200 ms ) and massive ( \ga 0.4 ~ { } M _ { \odot } ) white dwarf ( WD ) companions .
Recently , precise mass measurements have been performed for the pulsar and the WD in the IMBP PSR J1802-2124 .
Some observed properties , such as the low mass of the pulsar , the high mass of the WD , the moderately long spin period , and the tight orbit , imply that this system has undergone a peculiar formation mechanism .

Aims : In this work , we attempt to simulate the detailed evolutionary history of PSR J1802-2124 .

Methods : We propose that a binary system consisting of a neutron star ( NS , of mass 1.3 ~ { } M _ { \odot } ) and an He star ( of mass 1.0 ~ { } M _ { \odot } ) , and with an initial orbital period of 0.5 d , may have been the progenitor of PSR J1802-2124 .
Once the He star overflows its Roche lobe , He-rich material is transferred onto the NS at a relatively high rate of \sim 10 ^ { -7 } -10 ^ { -6 } ~ { } M _ { \odot } yr ^ { -1 } , which is significantly higher than the Eddington accretion rate .
A large amount of the transferred material is ejected from the vicinity of the NS by radiation pressure and results in the birth of a mildly recycled pulsar .

Results : Our simulated results are consistent with the observed parameters of PSR J1802-2124 .
Therefore , we argue that the NS + He star evolutionary channel may be responsible for the formation of most IMBPs with orbital periods \la 3 ~ { } d .

Conclusions :