Maryland could qualify next year for $420,000 in federal highway funds to combat drunken driving if the next General Assembly session adopts some tough drunken driving measures, including stiff mandatory penalties for drunk drivers.

The money will become available in February under a new law sponsored by Maryland Congressman Michael D. Barnes and signed by President Reagan last week. The law lays out four specific minimum criteria states must meet to be eligible for the money.

The four criteria include lowering to .10 the amount of alcohol a person can have in his or her blood to be automatically declared drunk; a mandatory 90-day license suspension for first offenders caught driving while drunk and a one-year suspension for repeaters; a mandatory 48-hour prison term or 10 days of community service for second offenders; and stepped-up enforcement coupled with a public awareness campaign.

The federal funds are intended to entice state legislatures nationwide to adopt stiffer laws, and to give added momentum to citizens groups that have been lobbying intensely for the same tough laws.

States that meet the federal standards are eligible for a grant of one-third the amount of federal money they already receive for highway safety programs.

The District, which now meets all but one of the criteria, would be eligible for about $140,000. The city currently does not meet the standard for the mandatory 48-hour jail term or 10 days of community service for second offenders.

Virginia would be eligible for $600,000 in additional highway safety funds under the program.

Virginia currently appears to meet three of the requirements, said Vince Burgess, administrator of the Virginia Alcohol Safety Action Program. The state's stepped-up public awareness and enforcement effort and mandatory 48-hour jail term or community service for second offenders help it qualify, he said.

In addition, first offenders in Virginia automatically lose their driver's licenses for six months, although the judge has the option of reducing that suspension if the convicted drunk driver enters a state alcohol safety program.

Burgess said Virginia now has no law automatically declaring a certain level of alcohol in the blood as proof of intoxication.

Maryland, which launched its own tough campaign against drunk drivers two years ago, now meets only one of the federal requirements: a public awareness campaign and increased enforcement of drunk driving laws.

The Maryland General Assembly, in its last round of tough drunken driving laws, lowered from .15 to .13 the level of alcohol needed in the blood for a person to be automatically classified as drunk.

Montgomery County Executive Charles W. Gilchrist and Del. Jerry Hyatt of Damascus said last week that they will lead the effort in next year's General Assembly session to bring Maryland into conformity with those state standards.

Hyatt said he felt it was important for Maryland to move first since it is Barnes' home state. Barnes added: "If we pass these bills, we can put Maryland into the forefront of states around the country."

Gilchrist and Hyatt said they will use the momentum of the drunken driving campaign to push for passage of another more controversial law not required for the federal money: a law requiring child protective seats in cars for any passengers under 4 years of age.