The invention relates to a self-defined modular bed. For the self-defined modular bed, each bearing bracket is arranged between a bearing soft cushion and a lifting structure for supporting the bearing soft cushion, an adjusting rail section is arranged on the bottom of each bearing bracket, when bed body units are in array arrangement, the adjusting rail sections are connected to form an adjusting rail, the adjusting rail is provided with adjusting parts, the adjusting parts comprise drive structures, the drive structures are used for driving the adjusting parts to move on the adjusting rail,the adjusting parts comprise a leaning part, a power supply part, a placing part, a storage part and an illuminating part according to the type; when the bed needs to be used for sleep, all the bed body units are controlled to be simultaneously positioned at the same horizontal height, then a support plane for lying of people is formed, thus the sleep demand is provided, when a user needs any function application, the drive mechanisms are controlled to act, then the corresponding adjusting parts move to the needed positions, the corresponding adjusting parts are controlled through the liftingstructures to extend out of the support plane, and the effect of the self-defined demand is achieved.