President Reagan has signed into law a half-dozen bills passed in the final days of the 100th Congress including legislation calling for stiffer penalties against insider trading and contractors who cheat the government.

The White House announced the bill signings on Saturday, although some took place earlier in the week.The bills signed by Reagan also concerned benefits to veterans who are alcoholics, protection of federal workers from liability lawsuits because of actions taken on the job; and approval of an unusual land deal involving Florida and Arizona.

The law on insider trading was designed to counter the wave of scandal that rocked Wall Street several years ago and shook the confidence of the nation's investors.

The measure doubles the maximum criminal penalties for insider trading from five years in jail to 10 years, and boosts fines from $500,000 to $2.5 million for a company and from $100,000 to $1 million for an individual.

Here is a summary of some of the bills that became law:

Contractor Penalties

The measure makes major government procurement fraud a federal crime and imposes tough, new penalties against contractors who have cheated the government. It is aimed at giving prosecutors new powers to deal especially with fraud involving Pentagon contracting.

The Defense Department has estimated that procurement fraud cost taxpayers $99.1 million in fiscal years 1986 and 1987.

Under the new law, those convicted of major fraud in government purchasing could be given prison sentences of up to 10 years and fined up to $10 million.

Land Swap

The law clears the way for a complex deal between a Florida man and the federal government in which some 107,800 acres of Florida swampland will be traded for a valuable piece of downtown government property in Phoenix, Ariz.

The bill authorizes the Interior Department to dispose of the 104-acre tract of Arizona land known as the Phoenix Indian School, which the Reagan administration wants to close because of declining enrollments.