Portable folding bicycle

The invention discloses a portable folding bicycle, and belongs to the field of bicycle structural design. With the improvement of people's environmental awareness, more townspeople select a 'bus plus bicycle' trip mode. However, bicycles are not allowed to be brought on buses in main domestic cities currently, so that the conflict can be solved by folding the bicycles into luggage sizes and bagging the folded bicycles. Through application of two dead center positions of double rocker mechanisms, a folding bicycle frame with good mechanical properties and being flat in shape and convenient to bag and carry after being folded is designed. Coupling of six groups of pairwise symmetrical four-rod mechanisms enables the degree of freedom of the folded bicycle frame to be 1, so that the bicycle frame is convenient to fold. The bolt-type fixation is convenient and reliable. Through matching between an upper handlebar folding mechanism and a saddle folding mechanism, the size of a folded bicycle body is not greater t