The three-day Rhodesian election that began today is being run on the basis of a party list system with voters casting their ballots for political parties rather than individuals.

It is only one of the unusual aspects of an election that has been organized from start to finish in slightly more than two months without the benefit of a census, registration or foolproof methods to prohibit voting by nonresidents or those under 18, the minimum voting age.

To avoid duplicate voting, since there is no registration list, voters must place their hands in a colorless liquid that shows for several days under an ultra-violet light used in the polling booth.

Britain has also taken other precautionary measures including printing the ballots in Britain, using special perforating implements to authenticate the ballot and employing unarmed British policemen to guard the ballot boxes overnight.

Voters simply mark the party of their choice among the nine represented on the ballot. Each party is identified by its initials and symbol.

African voters will choose 80 members of the lower house of Parliament on a proportional representation system in each of the eight provinces.

All parties receiving more than 10 percent of the vote in each province gain a share of the seats. Mashonaland East, which contains Salisbury, has the most seats with 16 while two districts in the sparsely populated north and south only have six each.

The election is being run by the Rhodesian civil service with supervision from Britain. Each of the 56 election districts will have at least one and as many as four British election supervisors.

There will be 657 polling stations, about half of them mobile to reach voters in remote areas. About 570 unarmed British policemen were deployed over the weekend to most of the polling stations to help monitor the elections.

In addition, almost 200 observers and their aides from more than 20 countries will be watching to see if the voting is free and fair. About 600 journalists are also covering the election.

It is estimated that there are about 2.9 million eligible voters. In last April's election, the first time blacks were even given the right to vote in Rhodesia, 64 percent cast ballots.