Gfilui

How can I get the present path as the parameter? And how can I pass this parameter to the ExecStart?

[Unit]
Description="xxxxxxx"

[Service]
EnvironmentFile='WORKDIR=/home/aaaa/bbbbb/' #I want to get this path dynamically when I put this in another path.
WorkingDirectory=/home/aaaa/bbbbb
ExecStart=/home/aaaa/bbbbb/server --database:/home/aaaa/bbbbb/cfg.json
ExecStop=/bin/sleep 5
KillMode=process
KillSignal=SIGQUIT
Restart=always
RestartSec=5s
LimitFSIZE=infinity
LimitCPU=infinity
LimitAS=infinity
LimitNOFILE=64000
LimitNPROC=64000
TasksMax=infinity
TasksAccounting=false

[Install]
WantedBy=multi-user.target

Systemd doesn't make the working directory accessible via specifiers, nor can you use environment variables in setting WorkingDirectory. You can use environment variables in ExecStart, but not for the command path. So, unless you use workarounds, you will have to specify the path at least thrice (note that you want Environment=, not EnvironmentFile=):

Environment='WORKDIR=/home/aaaa/bbbbb'
WorkingDirectory=/home/aaaa/bbbbb
ExecStart=/home/aaaa/bbbbb/server --database:$WORKDIR/cfg.json

Or, wrap your command in sh instead:

Environment='WORKDIR=/home/aaaa/bbbbb'
ExecStart=/bin/sh -c 'cd $WORKDIR; exec $WORKDIR/server --database:$WORKDIR/cfg.json'

(Hopefully your WORKDIR doesn't include spaces or other special characters in it.)

Or, if you make the unit a template, you can do:

Environment='WORKDIR=/%I'
WorkingDirectory=/%I
ExecStart=/%I/server --database:/%I/cfg.json

And do something like:

systemctl --user start my-service@home/aaaa/bbbbb.service

Note the leading slash / before the %I. The path to the executable must be absolute, with or without specifiers, so we need to use /%I.