The invention relates to a small waterline plane double-body leisure houseboat with multifunctional submerged body support. The small waterline plane double-body leisure houseboat comprises a boat house and a connecting bridge hull, wherein two multifunctional submerged body support systems are arranged on both sides of the connecting bridge hull; submerged bodies of the multifunctional submergedbody support systems are connected with retractable stay bar systems; the conversion of a three-body boat type and the small waterline plane double-body boat type is realized through the retraction and lowering of the retractable stay bar systems; propellers are installed at the tail of the submerged bodies, and ballast water tanks, control systems and underwater power systems are installed in thesubmerged bodies; and lifting stand column mooring systems are fixed around the boat house and the submerged bodies of a connecting bridge, and the lifting stand column mooring systems realize berthing of the three-body boat type, berthing of the small waterline plane double-body boat type and berthing of stand columns through lifting of the stand columns of the lifting stand column mooring systems, matching with stabilizer fin on the submerged bodies and positioning of a locking mechanism installed on the boat house. The small waterline plane double-body leisure houseboat meets the need of providing open deck space for sightseeing, and provides the need of comfortable enjoyment for passengers during traveling and berthing in waves.