That is held on March 3 which is one of five Sekku[節句（せっく）](the turning point of season), Momo no Sekku[桃の節句（もものせっく）](formally Jyōshi[上巳（じょうし）]). Momo is "peach" in Japanese. Peach blossoms bloom around March 3 on the lunar calendar. Therefore, it is called "Momo no Sekku".
Hina-matsuri is believed to derive from a purification ceremony introduced from China and dolls for playing house in the Heian Period(794-1185).
In the Heian Period, people transferred their harm and bad luck into human-shaped paper, and they floated it into a river or sea for expelling evil on Jyōshi.
At the same time, daughters of noble played house using dolls and miniature furniture and that was called "Hiina-asobi[雛遊び（ひいなあそび）]". These two integrated and Hina-matsuri came into existence.
On Hina-matsuri, there is a custom to eat some special food such as Hishi-mochi[菱餅（ひしもち）], Hina-arare[雛あられ], Chirashi-zushi[ちらし寿司（すし）], soup of Hamaguri[ハマグリ](a kind of clam), Shiro-zake[白酒（しろざけ）](white Sake).
Hishi-mochi is a rhombic Mochi[餅（もち）](rice cake). That mainly consists of red, a stack of pink, white and green Mochis. Hishi-mochi is also decorated with Hina-ningyō. Each color has its meaning: Pink = protection against evil or peach, White = cleanness or snow, Green = health and longevity or ground
Hina-arare is dried and sweetened small Mochi. They are mainly colored by four colors(pink, green, yellow, white) and it is said to express four seasons.
Chirashi-zushi is a kind of Sushi[寿司（すし）] and that is a vinegared rice topped with various colorful ingredients such as Renkon[蓮根（レンコン）](lotus root), green beans, shrimp. Each ingredient has auspicious meaning.