Whose is a working wife's salary? Must she give it to her husband?

A wife's salary belongs wholly to her, and she is not obliged to hand it to her husband or to fund the household.
Islam recognises women's independent ownership of property: men have a share of what they earn and women have a share of what they earn. Family maintenance remains the husband's obligation even if the wife is wealthier. If the wife contributes willingly, that is charity and kindness with great reward; female Companions such as Zainab, wife of Ibn Mas'ud, gave charity to their husbands and children. Couples should discuss openly and record large contributions such as house payments. See Rights of husband & wife and Maintenance.